Ivan Massow makes Boris Johnson look inhibited. As the most recent Conservative to declare himself a candidate to succeed Johnson as Mayor of London, Massow is revelling in the freedom “to blue sky”, which means to propose policies other politicians would shun as too risky.

In this interview, he reveals he is working on plans for the building of a huge new prison in the Thames estuary, to be called Ivatraz, which would enable London’s existing prisons to be redeveloped in order to help solve the housing crisis.

Massow criticises the recent sale of New Scotland Yard for giving away “four hundred million pounds’ worth of profit to a developer”, and defends his call for the City Hall building to be used to help the homeless.

When asked if he has enough discipline to be the Conservative candidate in London, Massow replies that Londoners would like a Mayor who is not too “on message”. But he expresses huge admiration for Lynton Crosby, and says he would like him, when available, to come and run his campaign.

His Ivatraz proposal emerged when ConservativeHome asked if he supports Johnson’s campaign for a hub airport in the Thames Estuary. Massow replied that he could think of a better use for that particular site: “One of the fun things we’re going to be looking at is whether instead of Alcatraz we should have Ivatraz. And this is a slightly jokey idea. We’ve seen an amazing development in Oxford where they’ve taken one of the prisons and turned it into amazing mixed use, wonderful accommodation, wonderful housing, funky bars and a huge shopping mall, and we realised that London is dominated by these prisons, sort of blighting these areas.

“I think you could quite easily look at a kind of a prison island and use some of these amazing sites for redevelopments as housing, and make a state-of-the-art correctional facility where Boris’s island was going to be. So we’re asking architects at the moment to draw this up just as a fun thing.

“And I love the idea like the old days of people being delivered to court by the river. Lots of the courts when you look at them are quite close to the river. People could go and visit their loved ones on a new river service that comes all the way up the river.”

ConHome: “I’m being slow. Why Ivatraz?”

Massow: “Because of Alcatraz.”

ConHome: “Yes, but why Iva?”

Massow: “Ivan-traz.”

ConHome: “Oh Ivantraz. Sorry, sorry, I see.”

Whether for Massow there will now be any escape from Ivatraz, more cautious spirits may doubt. But already he is outlining his next idea: he sees enormous potential for getting developers to rebuild hospitals and schools, so you end up with a beautiful new hospital or school, but also gain a large amount of new housing, some of which stays in public ownership and produces rental income.

He deplores the sale of valuable sites, such as New Scotland Yard, for a one-off profit: “Scotland Yard, I’m sure it’s an amazing deal, [but] I know about developers and it goes in thirds: land price, development cost, profit – third, third, third: that’s their ideal number.

“Someone accidentally has given away in my opinion £400 million pounds’ worth of profit to a developer on the Scotland Yard deal. It must be a lot of money if they’re prepared to spend £400 million buying it.”

ConHome: “Obviously a lot of readers of ConHome won’t know very much about you, so I hope you’ll be able to explain what kind of Conservative you are, and why you should be taken seriously. They may know you have a tremendous flair for publicity, and possibly that you are about to have a baby [with a lesbian couple he met online]. But they don’t know much about you politically.”

Massow: “I think I’ve been involved in the Conservative Party since about the age of 14 [he was born in 1967 so this would have been about 1981].”

ConHome: “This was in Brighton, was it?”

Massow: “In Rottingdean.”

He was first taken to the House of Commons by Julian Amery, the MP for Brighton Pavilion. Massow had a fractured childhood: he did not get on with his father or step-father, and at the age of about 12 he was adopted. As a young man he came to London and set up a successful financial services business selling insurance and mortgages to gay people, who in those days were often charged higher premiums and rates of interest.

ConHome: “Do you think you’ve got the discipline necessary for politics? One of the things people object to of course is that politicians are too on message. But are you sufficiently on message, do you think? Or perhaps as Mayor it’s best not to be on message?”

Massow: “For the job of Mayor it’s almost an advantage for at least your electorate to believe that you’re not as on message, that you’re not too restrained or restricted. The great thing about this role is that it’s about the candidate and about ideas, and there are very few areas in London politics that fall decisively into the Left or Right camp. Do you want cyclists to be able to turn left on a red light?”

ConHome: “Do you?”

Massow: “Yes.”

ConHome: “Good. Though as a cyclist myself, I think you should be polite, and not frighten old ladies.”

Massow: “We’re running a campaign about it.”

ConHome: “You can announce it via ConHome if you want.”

Massow: “It’s a Department of Transport issue. The current Mayor would I think quite like to do it. We’re just about to launch a petition site.”

Ideas for new ventures pour from Massow: “One of the things we’re talking about is a Festival of London – this hasn’t been launched either, I don’t mind if you mention it – every four years, a two-month huge Festival of London, based on the Festival of Britain, but this time to include food.

“And there’s a really good case to be put for potentially adding some sort of bedroom tax on hotel rooms, and we’re actually going to be doing an article in this week’s Huffington Post about that. We’re looking into how that works in Barcelona and Rome, and it does famously.

“We’re talking about a pound per star plus one. We think we can raise up to £350 million per year on that, and that’s quite a lot of money, when you think that the entire budget for dealing with London’s homelessness, schemes like No Second Night, operate on a budget of less than nine million pounds.”

“The sentiment was good and correct, but the reality is that further investigation suggests that Ken may have signed us into such a detailed lease [that the Mayor will have to go on using the building as offices]. But I am really interested in the whole issue about homelessness, but also its link to addiction.

“And I still think that from City Hall, though you may not have rows of bunk beds…it was a lovely idea, it was a real nice thing to do. I still think you can use City Hall more effectively, to showcase better practice.

“At this early stage of course there are other slightly fun ideas we’re looking at.”

ConHome: “What are the other fun ideas?”

Massow: “That are slightly more headline-grabbing. We have now 14,000 people signed up to our website in support of us. Now if you think that only 12,000 people engaged in the primary for Boris. And we haven’t even run the advertising campaigns and things that we need to do.”

ConHome: “You’re anticipating some serious opposition from other Conservative candidates?”

Massow: “Zac Goldsmith keeps saying he won’t run. But he might have a go. And Seb Coe, if he doesn’t get [the presidency of the IAAF], and that makes me wonder if they mightn’t leave the primary until after August to see whether Seb’s suddenly available. There’s talk of this guy called Michael Liebreich, who’s a Bloomberg guy. And Sol Campbell is interested in the job. [Unmentioned by Massow are Stephen Greenhalgh, currently a Deputy Mayor of London, who has said he will run, or Andrew Boff, a London Assembly member, who is also expected to be a candidate.]

“The reason I declared so early is that I probably need a little bit longer to prove myself, to build up policy and to build up a group of supporters, and make it clear to the party that I’m serious and I’m sticking at it, and that’s what I’ve been doing, and it’s been a full-time job – I have not stopped. I have enjoyed every moment so far, even the criticisms.”

ConHome: “What have the criticisms been?”

Massow: “On the whole the criticisms come from the Left, the normal ‘Tory wanker’.”

ConHome: “Oh that’s a compliment.”

Massow: “I think that’s a good sign. I think that means they think I am actually a threat. From my own party it’s been OK. I bumped into Steve Norris, he’s got his favourite line, ‘Is he Conservative or Labour these days?’ So that’s his put-down. But I’ve been on the candidates’ list, though I haven’t really applied for any seats, for something like five or six years.”

Massow was also on the candidates’ list in the late Nineties, when William Hague was leader: “And then I went and messed it up by throwing my toys out of the pram about Section 28. [In 2000 Massow resigned from the Conservatives, in protest against the party’s support for Section 28, and joined Labour.]

“On that issue, which cost me dearly, it did cost me dearly, that particular tussle with the party, but I thought it was the fastest way to bring the party to its senses, on issues like social inclusion and sexuality and tolerance, I felt it helped really illustrate the point.

“I was young and reckless and really passionate about it. I really believed it was a human rights thing, and incredibly important. I still do. David Cameron said recently, introducing single-sex marriage was one of the things he was most proud of in 2014.”

ConHome: “Will a higher proportion of gay people vote Tory as a result of same-sex marriage?”

Massow: “There is still a slight issue. There is still a stigma attached with the Conservative Party. It’s going to take another four years to wash that out completely. There is still a little bit there, but not as much, and many young people, they don’t even know about the issue. So young people are actually quite conservative when I speak to them.”

ConHome: “The Tories have the problem of being seen as the party of the rich. How does the party deal with that?”

Massow: “I don’t know.”

ConHome: “Good answer. You don’t get many politicians admitting that.”

Massow: “I actually feel quite bullish about the general election.”

ConHome: “Why?”

Massow: “I genuinely think people are enjoying messing with Cameron’s brain at the moment. But at the ballot box, when it comes down to it, everyone knows this is a serious one, a really serious one. And I think Lynton Crosby’s, ‘It’s the economy stupid’, is the right tack. It is just a focus on what’s important to people, which is feeling safe. So I actually think we’ll do well.”

ConHome: “So would you consider getting Lynton in to run your campaign?”

Massow: “I think Lynton’s king, yes. I like him. I like Australians generally. I like their no-nonsense approach, and I think he’s a good guy. But in the short term I’m working with other people. I’m getting advice from people like, I’m sure I can tell you, people I’ve always been close to like Dan Ritterband, who was senior in pre-Lynton days, and so at the moment I have to make do because Lynton’s busy. And expensive. “

ConHome: “Lynton was very rough with Boris. I’ve known Boris for a long time…”

Massow: “So have I.”

ConHome: “Yes, you must tell me about your early life with Boris.”

Massow: “No sex. Much as he tried.”

ConHome: “Journalistically I’ve had quite a lot to do with Boris since 1987. And in early 2008, suddenly he wouldn’t talk to you. If you saw him at an event, usually one of the reasons Boris gets enormous amounts of coverage is that he gives the journalists very good copy, he actually has things to say, and he knows it’s in his interests to be generous to his old trade. Anyhow, Lynton absolutely forced him to shut up for about three months. You couldn’t even get a joke out of him. It was very tiresome. That was Lynton, and it worked. He needed to reassure people that he was a serious character. But you’d be prepared to submit to the Lynton tyranny?”

Massow: “Well maybe he won’t need to with me. I’m so measured and on message. I really love good advice and I’m surrounding myself with wonderful people. I must say it’s given me a lot more confidence in myself. Because when you wrote that piece…”

ConHome: “Sorry, which particular piece?”

Massow: “Well not you. When your colleague wrote that little thing about my decision to declare. [Mark Wallace wrote a piece for ConHome in which he said: “I don’t think that Massow is a convincing candidate.”] It was quite hard, but I wrote to you I think saying I kind of deserve that.”

ConHome: “And what are your relations with Cameron and Osborne?”

Massow: “Osborne I’ve known for years and years and years, and that’s perfectly friendly. David Cameron I don’t really know very well. But I had a lovely letter from him the other day, very sweet, just congratulating me on putting my name forward, and inviting me, it wasn’t actually to meet him, saying make sure you pop in and see Grant Shapps and have a nice chat with him at your leisure, which I’m now doing. I’m seeing him tomorrow [i.e. Tuesday] evening.

“That only came last week, so that made me start to see I must be making the right sounds at last, because I didn’t certainly get that kind of reception on day one. I didn’t get a negative reception. It was just very, very quiet.”

This interview was carried out in Massow’s kitchen, which covers the ground floor of his terraced house in Bloomsbury, just behind Great Ormond Street Hospital. Throughout the conversation, a curious clicking and scuffling could be heard coming from the other end of the room.

Massow: “You’ve just noticed the parrot.”

ConHome: “Well I’ve been hearing the parrot all through. What’s the name of the parrot?”

Massow: “That’s Clio.”

ConHome: “C-L-I-O?”

Massow: “Oh please don’t ask a dyslexic how his parrot spells its name.”

ConHome: “I just don’t want to get it wrong.”

Massow: “I’ve never actually asked her how she spells her name.”

ConHome: “Does she ever say anything?”

Massow: “She will do. She’s an African grey, but she’s very young. She comes from a rescue home. There are two more at the back, called Elizabeth and Romeo.”

Massow talks much, and often very amusingly. One can see why Joan Collins is his friend. He has a generosity of enthusiasms – art, fox-hunting, the homeless – and unlike many Englishmen, is prepared to admit his vulnerability. He will enliven the contest to be Tory mayoral candidate by saying things no one else would dream of saying.